Internal combustion engine and working cycle

ABSTRACT

An internal combustion engine provides cooler working cycle and, selectively, mean effective cylinder pressure higher than conventional Otto and Miller cycle engine arrangements. According to one embodiment, during each cycle, intake valve is held closed during the initial portion of the intake stroke and then opened and closed. In another embodiment, during each cycle, intake valve opens twice, once opening and closing during the intake stroke and, then opening and closing again. In all embodiments, the last intake valve closing of the cycle is during the compression stroke at a point which captures a charge weight needed to power the engine and at such time that the effective compression ratio of the engine will be less than the expansion ratio. The combustion chambers, engine stroke and/or cylinder bore are selectively sized. An expansion valve is alternately provided to cool entry air, and may have a controllable, variable orifice.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of provisional patent application No. 60/495,997, filed Aug. 18, 2003.

BACKGROUND OF THE INVENTION

This invention relates to a method of deriving mechanical work from combusting gas in an internal combustion engine by means of a new thermodynamic working cycle and to reciprocating internal combustion engines for carrying out the method.

As the expansion ratio of an internal combustion engine is increased, more energy is extracted from the combustion gases and converted to kinetic energy, increasing the thermodynamic efficiency of the engine. Increasing air charge density increases both power and fuel efficiency due to further thermodynamic improvements. Typical objectives for an efficient engine are to provide a high-density charge, begin combustion at maximum density and then expand the gases as far as possible against a piston

SUMMARY OF THE INVENTION

Briefly described, the present invention comprises an internal combustion engine system (including methods and apparatuses) for managing combustion charge densities, temperatures, pressures and turbulence in order to produce a true mastery within the power cylinder in order to increase fuel economy, power and torque while minimizing polluting emissions. In its preferred embodiments, the method includes the steps of (i) producing an air charge, (ii) controlling the temperature, density and pressure of the air charge (iii) transferring the air charge to a power cylinder of the engine such that an air charge having a weight and density selected from a range of weight and density levels ranging from atmospheric weight and density to a heavier-than-atmospheric weight and density is introduced into the power cylinder, and (iv) then compressing the air charge at a low “effective” compression ratio, (v) causing a pre-determined quantity of charge-air and fuel to produce a combustible mixture, (vi) causing the mixture to be ignited within the power cylinder, and (vii) allowing the combustion gas to expand against a piston operable in the power cylinder with the expansion ratio of the power cylinder being substantially greater than the effective compression ratio of the power cylinders of the engine. In addition to other advantages, the invented method is capable of producing mean effective [cylinder] pressures (“mep”) which are much higher than produced by traditional Otto, Miller and Diesel cycle engines. In the preferred, but not all, embodiments, the mean effective cylinder pressure is alternatively, selectively variable (and selectively varied) throughout a wide range during the operation of the engine.

Many principles and structures of relevance to the present invention are found in the disclosures of my prior U.S. patent application Ser. Nos. 08/863,103 (now U.S. Pat. No. 6,279,550) and 10/385,588; which disclosures including specification and drawings as well as the disclosure of U.S. provisional application Ser. No. 60/495,997 are all hereby incorporated herein in their entirety by reference.

In its preferred embodiments, the apparatus of the present invention provides a reciprocating internal combustion engine with at least one ancillary compressor for compressing an air charge, an intercooler through which the compressed air can be directed for cooling, power cylinders in which the combustion gas is ignited and expanded, a piston operable in each power cylinder and connected to a crankshaft by a connecting link for rotating the crankshaft in response to reciprocation of each piston, transfer conduit communicating an atmospheric inlet port to the inlet of at least one compressor, a transfer conduit communicating the compressor outlet to a control valve and to the intercooler, a transfer manifold communicating the intercooler with the power cylinders through which manifold the compressed charge is transferred to enter the power cylinders, an intake valve controlling admission of the compressed charge from the transfer manifold to said power cylinders. For the 4-stroke engine of this invention, the intake valves of the power cylinders are timed to operate such that charge air which is (by weight of air per liter) equal to or heavier than charge air utilized in traditional Otto, Miller and Diesel cycle engines can be maintained within the transfer manifold when required and introduced into the power cylinder during the intake stroke, with the intake valve closing at some point during the compression stroke, to provide a low “effective” compression ratio.

According to one embodiment, the intake valve is held closed during the initial portion of the piston intake stroke and then opened and closed in a manner to create and maintain a compression ratio less than the expansion ratio so that ignition can commence at substantially maximum charge density. Means are provided for causing fuel to be mixed with the air charge to produce a combustible gas. In another embodiment, the intake valve can open twice, once opening and closing during the intake stroke and again opening during the later part of the intake stroke, or later, and closing during the compression stroke at a point which captures a charge weight needed to power the engine and at such a time that the effective compression ratio of the engine will be less than the expansion ratio so that ignition can commence at substantially maximum charge density. Means are provided for causing fuel to be mixed with the air charge to produce a combustible gas.

In both systems compression continues and the charge is ignited near TDC for the power stroke, followed by scavenging stroke.

The combustion chambers of the power cylinders are sized with respect to the displaced volume of the power cylinders such that the exploded combustion gas can be expanded to a volume substantially greater than the effective compression ratio of the power cylinders of the engine. The combustion chambers are of a size to establish compression ratios similar to those of a typical Otto or Diesel cycle engines or alternatively are enlarged for more power. In some embodiments where combustion chambers are enlarged, engine stroke and/or cylinder bore are increased to match, concurrently, the increase in charge-air expansion.

In alternate versions of both of the mentioned embodiments, one or more expansion valves are provided in the path of air introduction to the intake valve to effect a chilling of entry air; and the expansion valve can be provided with one or more controllable, variable orifices.

The chief advantages of the present invention over, for example, existing Otto and Miller cycle internal combustion engines are that it provides a cooler working cycle with an effective compression ratio lower than the expansion ratio of the engine and significantly lower than effective compression ratios of Miller cycle engines; and the present invention, provides, selectively, a mean effective cylinder pressure higher than the conventional Otto, Miller and Diesel cycle engine arrangements. These allow greater fuel economy and production of significantly greater power and torque at all RPM, with low polluting emissions.

Various other objects, features, and advantages of the present invention will become more apparent upon review of the detailed description set forth below when taken in conjunction with the accompanying drawing figures.

A BRIEF DESCRIPTION OF DRAWINGS

FIG. 1, is a perspective view (with portions schematically illustrated or in cross-section) of sections of an internal combustion engine operating in a four-stroke cycle showing a portion of the engine block, one cylinder with piston, and a section of the head showing an intake valve and an exhaust valve with compressors, inter-coolers and controls from which a first method and a second method of operation can be performed and will be described.

FIG. 2, is a perspective view of a partial engine block and head in cross-section and showing a cylinder of an engine with the intake valve operated by a camshaft and cam, the cam having two lobes for opening and closing the intake valve twice during each power cycle. Shown also, is a second valve control arrangement illustrating a cam with single lobe which will alternatively operate in a known manner.

DETAILED SPECIFICATIONS AND OPERATION Model I Single Valve—or Multiple Valves in Unison Opens Once Each Power Cycle

Referring to FIG. 1, the engine of this invention is a high efficiency engine that attains both high power and torque with low fuel consumption and low polluting emissions. The new working cycle is an external compression type combustion cycle. In this cycle, the intake air is selectively compressed by at least one ancillary compressor 1, 2. The temperature rise during compression can be suppressed by use of air coolers 10, 11, 12, which cool the intake air, and by a shorter effective compression stroke.

One suggested preferred method of operation of the new cycle engine is thus: this first embodiment comprises a supercharged internal combustion engine in which, selectively, atmospheric air or air-fuel mix is compressed and cooled externally to the engine and introduced during the intake stroke or shortly thereafter, and the intake valve is then closed during the compression stroke at a point that the retained charge weight within cylinder/combustion chamber is sufficient, when mixed with fuel and ignited at piston top-dead-center (TDC), to produce the power and torque desired of the engine. During the first stroke, normally an intake stroke, the intake valve is held closed during the initial part of the stroke. In this system, this first stroke expands any residual gases in the combustion chambers. These expanding gases cool piston and cylinder and enhance the entrance of the air charge which is inducted at some point before or after piston bottom-dead-center (BDC) of the first stroke.

Operation

(1) Atmospheric air is received by port 8, filtered, compressed by compressor of turbo charger 1, is passed through after cooler 10, then alternatively, further compressed and temperature adjusted by wholly or partially passing through compressor 2, wholly or partially through intercooler 11 (which is alternatively water cooled), then passed wholly or partially through after-cooler 12 and through conduit B, through intake valve 16 and intake port 416 into chamber 407. The chamber 407 is that chamber formed, in this embodiment by the piston 7 top, cylinder 7 walls, and engine head 404. Alternatively, conduit B contains an expansion valve 410 (or, again optionally, intake port 416 is fitted with an expansion valve) as shown and illustrated in conduit B. Alternatively, conduit to compressor 2 is fitted with an air bypass system consisting of bypass valve R1 and conduit X1; conduit to intercooler 11 is fitted with bypass valve R2 and bypass conduit X2, conduit from intercooler 11 to intercooler 12 is fitted with a bypass valve R3 and bypass conduit X3, whereby the valving and bypass system so constructed that said R control valves, activated by sensors within the system, send messages concerning temperatures of the passing fluid to alternate engine control module, ECM-27 to alternatively cause R valves to individually pass the transmitted fluids wholly or partially through intercoolers or cause wholly or partially to bypass the compressor 2 or cooler 12, 13, in order to adjust pressure and temperature to that desired for best engine performance. Expansion valve 410, regardless of position in the inlet conduit, has, alternatively, a variable orifice (opening) controlled alternatively by ECM-27 which adjusts the size of the orifice, if present, to that producing a desired temperature of the charge air. The very high pressure air or air-fuel charge is delivered to intake valve 16 and inlet port 416 and is utilized in this fashion:

(2) Valve 16 and inlet port 416 are kept closed through the first part of the first (normally intake) stroke.

(3) At a time deemed optimal, before piston 22 bottom-dead-center or after, intake valve 16 and inlet port 416 open to induct the cool, dense air or air-fuel charge into the chamber 407. The valve 16 is held open long enough that the charge inducted has time to fill chamber 407 and, possibly for piston 22, during compression (2^(nd)) stroke, (alternatively) to expel a portion of charge back through intake port 416 and valve 16 and into manifold 14. Alternatively any excess charge is expelled through an ancillary valve (not shown) with proper back pressure to prevent pressure drop. Port 416 and valve 16 are then closed at a predetermined point of piston 22 travel in the compression stroke. In alternate embodiments, the point of closure of intake valve 16 and inlet port 416 is variable and varied using, for example, valve controlling devices known in the industry. When the port and valve are closed, a charge is trapped and retained which when mixed with fuel, if not already present, and ignited will cause the engine to produce the power and torque required of the engine at that moment. According to preferred, but not all, embodiments, the point of closure of the intake valve 16 and inlet port 416 occurs after the piston has traveled through a meaningful portion of the compression stroke, for example, at or after 25% and, preferably, after 50% of the compression stroke has been traveled. More preferably, in alternate embodiments, the closure takes place as late as possible in the compression stroke while still providing enough time after the closure for the trapping of air to be complete and ignition of the fuel/air combination to take place no later than at the point of piston top dead center at the end of the compression stroke. According to one example, the closure of intake valve 16 and inlet port 416 occurs at a point in piston travel of approximately 15°-20° before top dead center.

(4) Compression continues on the trapped portion of charge and near piston 22 top-dead-center, the charge is fueled, if fuel is not present, and ignited, producing great power, for the power/expansion (3^(rd)) stroke, followed by the scavenging (4^(th)) stroke to complete one power cycle.

Model II Single Valve—or Multiple Valves in Unison Intake Valve Opens Twice Per Power Cycle

Referring to FIG. 2, with reference to FIG. 1 for similar components—This system is much like the Model I with exceptions:

MODE ONE

(1) Atmospheric air or air-fuel is inducted by inlet duct 8, filtered into and compressed by turbo charger 1, further compressed by compressor 2, cooled by at least one of intercoolers 10, 11 and 12. The charge has its temperature and pressure adjusted by compressor and cooler system the same as for the engine of Model I. The optimal charge is inducted, cool or “chilled”, by intake conduit B, intake valve 16B and inlet port 416B (shown in FIG. 2). The chief difference of this engine operation as compared to Model I is that inlet port 416B is opened and closed twice by valve 16B of FIG. 2, for example, with double-lobed cam 21, with lobes 21C and 21D each opening valve 16B and inlet port 416B once during each power cycle.

As in Model I, the air or air-fuel charge alternatively, has its pressure and temperature adjusted by the compression-cooling-bypass system, alternatively controlled by engine control module (ECM-27), FIG. 1. In addition, the cool, high-pressure air, as in the engine of Model I, can be thermodynamically “chilled” by being expanded by expansion valve 410 as indicated within conduit B of FIG. 1 and FIG. 2, or by the same system at valve inlet port 416A.

(2) Atmospheric air inducted by port 8 of FIG. 1 and pressure and temperature adjusted as specified is introduced by valve 16B and port 416B, of FIG. 2, in the following manner:

-   -   (a) Intake valve 16B of FIG. 2, (being either cam 21 operated         with cam 21 having two lobes 21D and 21C, or operated by a         quick-acting valve controller such as valve controller 21′ of         FIG. 1, including but not limited to electrical, hydraulic, or         mechanical operation) is opened quickly with low valve lift         during part of the intake (1^(st)) stroke of piston 22. Intake         valve 16B, with cam lobe 21D of FIG. 2 or valve controller 21′         of FIG. 1 closes quickly, capturing a light charge in the         initial charge intake. This small air charge is expanded during         any further piston 22 intake movement, providing some cooling to         piston and cylinder, with little air charge remaining to create         heat during the compression stroke.     -   (b) At a point after closure of the intake valve 16B of FIG. 2,         either (i) during the intake stroke or (ii) after piston 22         bottom-dead-center during the first part of the compression         stroke, intake valve 16B and port 416B is opened again. The         valve is opened at a predetermined point that will allow time         for fluid to flow freely from intake manifold 14 (in FIG. 1)         through conduit B, through inlet port 416B and into chamber 407.     -   (c) At a time deemed optimal, at a point, or after, valve 16B         and port 416B has first closed, whether before piston 22 BDC or         after, intake valve 16B and inlet port 416B open again by cam         lobe 21-C (or by valve 16 of FIG. 1) to induct a heavy, cool, or         chilled (e.g., chilled by compression-expansion), dense air or         air-fuel charge into the chamber 407 of cylinder 7. The port         416B is held open long enough for the cylinder 7 (shown in FIG.         1 and FIG. 2) to receive sufficient charge to fill the chamber         407 and possibly for piston 22 (shown in FIG. 1), during the         compression stroke, to expel any excess portion of charge back         through intake port 416B and valve 16B and back into manifold 14         (of FIG. 1). Alternatively, excess charge is expelled through an         ancillary valve (not shown) with proper back pressure to prevent         pressure drop.     -   (d) For example, Port 416B and valve 16B are held open by lobe         21C of cam 21, FIG. 2 or by quick-acting valve 16 of FIG. 1,         during the last part of the intake stroke and/or first part of         the compression stroke. Port 416B and valve 16B are then closed         at a predetermined point of piston 22 travel in the compression         stroke. In alternate embodiments, the point of closure of intake         valve 16B and inlet port 416B is variable and varied using, for         example, valve controlling devices known in the industry. When         the port and valve are closed, a charge is trapped and retained         which when mixed with fuel, if not already present, and ignited         will cause the engine to produce the power and torque required         of the engine at that moment. According to preferred, but not         all, embodiments, the point of closure of the intake valve 16B         and inlet port 416B occurs after the piston has traveled through         a meaningful portion of the compression stroke, for example, at         or after 25% and, preferably, after 50% of the compression         stroke has been traveled. More preferably, in alternate         embodiments, the closure takes place as late as possible in the         compression stroke while still providing enough time after the         closure for the trapping of air to be complete and ignition of         the fuel/air combination to take place no later than at the         point of piston top dead center at the end of the compression         stroke. According to one example, the closure of intake valve         16B and inlet port 416B occurs at a point in piston travel of         approximately 15°-20° before top dead center.     -   (e) Compression continues and near piston 22 TDC, fuel is added,         if not present, and the charge is ignited, producing great         power, for the power/expansion (3^(rd) stroke), followed by the         scavenging (4^(th) stroke) to complete one power cycle.

Referring again to FIG. 2, there is shown a system whereby the engine of this invention described for Mode One heretofore, can alternatively operate in a second and a third mode.

MODE TWO

In Mode Two, valve 16A, has a cam 21B on which a single lobe 21E has a profile matching lobe 21C on cam 21, which cam 21 opens and closes valve 16B and inlet port 416B. Lobe 21D of cam 21 is missing on cam 21B. Therefore, alternatively, this arrangement is constructed such that during each firing cycle: (a) lobe 21D first opens and closes valve 16B during an intake stroke of piston 22; and (b) subsequently, and in unison or approximately in unison, lobe 21C and lobe 21E open and close their respective valves 16B, 16A and ports 416B, 416A. This permits much faster charging of the chamber 407.

The engine can operate in this mode continuously as “steady-state” power for heavy duty operation.

MODE THREE

The engine of Model II of FIG. 2 can be operated alternately and intermittently in either Mode One or Mode Two, which becomes Mode Three, operation. In this mode, (i) by engaging the drive of cam 21 and engaging the drive of cam 21B the engine operates in Mode Two, hence, as Mode Two engine and, (ii) by then disengaging cam 21B's drive and engaging cam 21 the engine operates in Mode One.

In this “intermittent” mode, (Mode Three), the engine can operate in Mode One for cruising or at any time less power is required, and can then be switched to Mode Two at anytime great power is needed. Engaging and disengaging the cam 21B can be accomplished in any of numerous ways known in the art of valve and cam control.

It will be seen by the foregoing description of a plurality of embodiments of the present invention, that the advantages sought from the present invention are common to all embodiments.

While there have been herein described approved embodiments of this invention, it will be understood that many and various changes and modifications in form, arrangement of parts and details of construction thereof may be made without departing from the spirit of the invention and that all such changes and modifications as fall within the scope of the appended claims are contemplated as a part of this invention.

While the embodiments of the present invention which have been disclosed herein are the preferred forms, other embodiments of the present invention will suggest themselves to persons skilled in the art in view of this disclosure. Therefore, it will be understood that variations and modifications can be affected within the spirit and scope of the invention and that the scope of the present invention should only be limited by the claims below. Furthermore, the equivalents of all means-or-step-plus-function elements in the claims below are intended to include any structure, material, or acts for performing the function as specifically claimed and as would be understood by persons skilled in the art of this disclosure, without suggesting that any of the structure, material, or acts are more obvious by virtue of their association with other elements. 

1. Method of operating an internal combustion engine, which engine includes a piston cycling in a cylinder through at least an intake stroke and a compression stroke, said method comprising the steps of preventing entry of air into the cylinder during an initial part of the intake stroke and then opening an intake port to the chamber and closing the intake port at point of piston travel in the compression stroke.
 2. Method of claim 1, including the step of cooling pressurized air and inducting the cooled, pressurized air into the cylinder through the open intake port.
 3. Method of claim 2, wherein the cooling step includes the step of expanding air through an orifice prior to entry of the air through the intake port.
 4. Method of claim 3, further including the step of selectively controlling the size of the orifice.
 5. Method of claim 1, wherein the step of closing the intake valve includes closing the intake port at a predetermined point of piston travel in the compression stroke.
 6. Method of claim 1, wherein the step of closing the intake valve includes varying from one cycle to another the point of closing of the intake valve.
 7. Method of claim 1, wherein the step of closing the intake port includes closing the intake port at a point of piston travel as late as possible in the compression stroke while still providing enough time for ignition to take place no later than at piston top dead center.
 8. Method of claim 1, wherein the step of closing the intake port includes closing the intake port at a point of piston travel which point falls within the range of greater than or equal to 25% of the compression stroke and 15° of piston travel before top dead center of the compression stroke, inclusive.
 9. Method of operating an internal combustion engine, which engine includes a piston cycling in a cylinder through at least an intake stroke and a compression stroke, said method comprising the steps of opening and closing an intake port to the cylinder twice during each cycle of the piston, wherein the first opening occurs prior to or during the intake stroke and the second closing occurs at a point of piston travel in the compression stroke.
 10. Method of claim 7, including the step of cooling pressurized air and inducting the cooled, pressurized air into the cylinder through the open intake port.
 11. Method of claim 10, wherein the cooling step includes the step of expanding air through an orifice prior to entry of the air through the intake port.
 12. Method of claim 11, further including the step of selectively controlling the size of the orifice.
 13. Method of claim 9, wherein the step of closing the intake valve includes closing the intake port at a predetermined point of piston travel in the compression stroke.
 14. Method of claim 9, wherein the step of closing the intake valve includes varying from one cycle to another the point of closing of the intake valve.
 15. Method of claim 9, wherein the second closing occurs at a point of piston travel as late as possible in the compression stroke while still providing enough time for ignition to take place no later than at piston top dead center.
 16. Method of claim 9, wherein the second closing occurs at a point within the range of 25% of the compression stroke and 15° before top dead center, inclusive. 